Plug the power and power up the PC (either auto-on or pressing power button).

LED-B (BIOS)*
This LED is Yellow after display initialization.
If BIOS setup menu is needed, the DEL button is functional from the moment the B-LED is Yellow.
The B-LED is Green when the OS takes charge of the system.

*LED Diagnostics feature is available only for models configured the with FM-AT3 FACE module